Method for manufacturing a structural component for a turbomachine

ABSTRACT

A method for producing engine components with a complex geometric structure particularly for an aircraft engine, includes providing a first component that has a first sintered state with a first degree of compaction; providing at least one second component that has a second sintered state with a second degree of compaction; wherein the second degree of compaction is lower than the first degree of compaction; and wherein the at least one second component has an opening, into which a portion of the first component is introducible; and wherein the opening is dimensioned to close substantially completely during a sintering joining process, to form a force-fitting sintered joint with the first component; introducing the first component into the opening; and carrying out the sintering joining process.

This application claims priority to German Patent Application DE102018212624.0 filed Jul. 27, 2018, the entirety of which is incorporated by reference herein.

The present disclosure relates generally to engine technology. In particular, the present disclosure relates to the production of engine parts with a complex geometric structure. More particularly, the present disclosure relates to a production method for an engine component made of two components that have different degrees of compaction.

Joining is a suitable production method for complex parts or groups of parts, in particular for parts in the aerospace sector, which can be produced integrally only with difficulty, if at all. In this context, there are various joining techniques, for example welding, brazing, adhesive bonding, but also screwed joints and mechanical joints designed in some other way. At the same time, however, it is not possible to join all workpieces because, for example, the materials used are insufficiently suitable for welding or brazing or because the joining methods can be provided only with additional weight being involved, in the case of a screwed joint for example, or only with limited temperature stability being involved, in the case of adhesive or brazed joints.

One form of joining is sintering. Here, preforms, which have been produced for example by means of powder injection molding or by means of conventional powder pressing methods, are consolidated. The powder injection-molding method consists substantially of the process steps of injection molding, binder removal and sintering. During the sintering process, volume shrinkage occurs, since particles in the initial part move together and are joined.

In order to improve the quality of a sintered joint, it may be advantageous for a force to act on the components to be joined during the joining process. As a result of this force, a preferred joint, and thus a joint with greater joining quality, arises in the joining region of components to be joined.

Sintering joining is a joining method in which at least two components are in direct contact, at a joining surface. During the sintering joining process, the temperature of the components is increased, resulting in the coalescence of the grain structures in the polycrystalline starting materials. Typically, sintering is carried out at a temperature which is slightly below or even slightly above the melting temperature of the components to be joined.

Depending on the geometric complexity of a part to be produced, it may not, however, always be possible to produce such a part integrally in a single injection-molding process. In particular when a part having complex or self-supporting structures is intended to be produced, deformation of the part may occur during sintering, on account of the force of gravity acting thereon and of low stiffness or strength of the starting material. Conventionally, deformation during the sintering process may be countered by the provision of special supporting structures.

An example of such a complex part that may be mentioned is, for example, a double ended stator vane, i.e. a blade airfoil for a turbomachine having a tip shroud. Such a part can be produced integrally in one production step only with difficulty on account of its complex geometric structure. In particular, although a double-ended stator vane may be produced integrally, during sintering it may experience severe deformation on account of gravity, and this can result in non-conformity of the part for a required use purpose. Furthermore, it may be necessary to provide the above-described complicated supporting structure in order to reduce or minimize deformations.

Therefore, there may be a need to implement joining methods that are suitable specifically for aeronautical applications in order to produce complex integral parts.

There may furthermore be a need, in the case of a joining process of this kind, to be able to implement further measures, thereby enabling a preferred joint and thus a joint with enhanced joining quality to be realized.

At least such a need may be met by the subject matter of the independent claims. Preferred embodiments can be found in the dependent claims and are explained in more detail in the rest of the description.

According to a first aspect of the present disclosure, a method for producing a complex part for a turbomachine, in particular for an aircraft engine, is indicated, having the steps of providing a first component that has a first sintered state with a first degree of compaction; providing at least one second component that has a second sintered state with a second degree of compaction, wherein the second degree of compaction is lower than the first degree of compaction and wherein the at least one second component has an opening, into which a portion of the first component is introducible, and wherein the opening is dimensioned in such a way as to close substantially completely during a sintering joining process, in order to form a force-fitting sintered joint with the first component; introducing the first component into the opening; and carrying out the sintering joining process.

According to a second aspect of the present disclosure, a part for a turbomachine, in particular for a gas turbine engine for an aircraft, and more particularly for an aircraft engine, is provided, produced by the method according to the present disclosure.

According to a third aspect of the present disclosure, a gas turbine engine for an aircraft is provided, having at least one part according to the present disclosure, in particular produced by the method according to the present disclosure.

Ideas and concepts in the present disclosure may be regarded as being based on the following observations and insights.

The present disclosure describes a method for producing a complex part from two or more components in a sintering process, wherein a substantially integral part results from the joining process.

Components for a sintering joining process are first of all produced as part of a preparatory process, for example a metal powder injection-molding method, in which a powdered material is mixed with a binder and processed into a molding in an injection-molding process. A molding produced in this way is also referred to as a green compact. In a subsequent step, the binder is removed, being dissolved or removed by means of thermal treatment, for example. A resultant molding is referred to as a brown compact.

In a subsequent sintering process, the brown compact is raised to a temperature slightly below or slightly above the melting temperature of the materials thereof, resulting in a consolidation reaction of the materials of the component and a simultaneous reduction in the dimensions thereof. A fully sintered part thus has reduced dimensions compared with a green compact and a brown compact. Typical shrinkage may be in the range of 10 to 30%.

Such a change in state during the shrinking operation or the sintering process may also be expressed in terms of a degree of compaction. In other words, a component in the form of a brown compact or green compact has a lower degree of compaction than a fully sintered part. Also conceivable is only partial sintering or pre-sintering, in particular at a lower temperature than the actual sintering temperature and/or with a shorter holding time at the sintering temperature, with the result that the shrinkage may not be realized to its full extent. Thus, it is possible for example for a component to have experienced only shrinkage of 20% in a pre-sintered state, which, although it would have undergone shrinkage of for example 30% at the end of an entire sintering process, with the result that there would still be a residual shrinkage capacity of 10% (in a further sintering process). Such a pre-sintered component thus has a lower degree of compaction than a fully sintered component.

In the context of the present disclosure, a sintered state may be understood as being any state of a component in the sintering process. In particular, a component may be in the form of a green compact or brown compact, or the component may be pre-sintered or fully sintered. Sintered state should in particular not be understood with the limiting meaning that the component has already been subjected to a sintering process, even one that has been only partially effected.

The present disclosure thus describes a production method for a complex part made of at least two components that have for example different degrees of compaction. As a result, a first component exhibits different shrinkage at the end of a joining process than a second component. If an opening is provided in a component having a lower degree of compaction, with a portion of the other component having a higher degree of compaction being introduced into said opening, an integral part is producible on account of the different degrees of compaction with associated different shrinkage. If, for example, the component in which the opening is formed has a lower degree of compaction than the other component, this means that this component having a lower degree of compaction has undergone greater shrinkage or residual shrinkage following the sintering joining process than the component having a higher degree of compaction. As a result of suitable dimensioning of the opening, the dimension of the opening may thus shrink (disproportionately) compared with the dimension of the introduced component, such that, during or after the sintering joining process, the material of the first component is in contact with the material of the second component and in the process forms a sintered joint, with the result that an integral part is producible.

Alternatively, the second component is in a state in which it has been subjected to binder removal (brown part) and the component to be enclosed is in turn in a pre-sintered or a fully sintered state. In the context of the present disclosure, a component that is already fully sintered may also be used as a component in a sintering joining process and nevertheless forms a conventional sintered joint with a pre-sintered component or a brown part. Depending on the degree of shrinkage, in the state before the sintering joining process, a suitably dimensioned gap should be provided between the first component and second component, such that this gap is substantially closed after the sintering joining process on account of the disproportionate shrinkage of the first component. Different shrinkage may also be provided by different materials, for example a combination of a nickel alloy with a cobalt alloy, being provided for the first and the second component, or it is also possible for different powder/binder mixtures (known as feedstocks) with different binder contents (for example the same or different metal powder) to be used for the first and the second component.

As a result of the first component shrinking onto the second component, a contact pressure may be generated, which may be advantageous for the quality of the joint. On account of its not fully sintered state, the first component has good sintering activity, for example caused by the brown state or a merely pre-sintered state, and this may likewise be advantageous for the quality of a sintered joint to be formed.

The method according to the present disclosure can in this case be used for different materials, for example between same-type or different-type ceramic-to-ceramic joints, same-type or different-type metal-to-metal joints, or metal-to-ceramic or ceramic-to-metal joints.

The production of a blade airfoil with a tip shroud, i.e. of a double-ended stator vane may be mentioned as a specific example. In the context of the present disclosure, such a vane may be produced integrally by sintering joining the tip shroud to an already (pre-)sintered blade airfoil, or single-ended stator vane. A single-ended stator vane may be produced for example from a nickel-based alloy (for example In713LC) via a metal injection-molding (MIM) process and may subsequently be pre- or fully sintered. The tip shroud of the double-ended stator vane may have been produced by means of MIM from the same material as the single-ended stator vane and for example merely have been subjected to binder removal or pre-sintered. In the tip shroud, an opening or a groove may be provided, which substantially replicates the cross section of the single-ended stator vane at the blade tip. The groove can in this case be formed either continuously or discontinuously. Different designs in the joining region of the tip shroud and blade airfoil are possible, in order to take account of aerodynamic, strength-related and MIM-process-related aspects. The tip shroud that has been subjected to binder removal will, for example in order to carry out the sintering joining process, be plugged onto the sintered single-ended stator vane. Depending on the shrinkage behavior, a gap may be provided before sintering joining. Shrinkage of the tip shroud may be for example between 10-20%, in particular 14-18%, more particularly 16.4%. The gap size, i.e. the distance from the blade airfoil (first component) to the tip shroud (second component), may amount to 0-100% of the shrinkage or of the shrinkage difference between the first and second components, in particular 60%. The tip shroud may optionally be supported during sintering joining, in order to avoid deformations.

According to one embodiment of the present disclosure, before the sintering joining process is carried out, a slot may be provided, in particular in the region of the opening, between the first and second component, wherein the slot may be closed substantially completely after the sintering joining process has been carried out.

In other words, the opening is dimensioned such that the first component can be introduced into the opening in the second component with a slight spacing, i.e. with a slot or play. As a result of the different configurations of the degrees of compaction, and thus different shrinkage while the sintering joining process is being carried out, the slot may be substantially closed, i.e. no longer present, after the sintering joining process has been carried out. Any prior spacing between the first and second component may thus close up, with the materials of the first and second component, which form a joint while the sintering joining process is being carried out, resting against one another.

According to a further embodiment of the present disclosure, the second component may shrink more than the first component while the sintering joining process is being carried out, with the result that the opening or the slot may close substantially completely.

Such different shrinkage may in this case be caused by different degrees of compaction, different materials and/or different binder contents. For example, the second component has a degree of compaction that corresponds to prior shrinkage of 5%, while the first component has a degree of compaction that corresponds to prior shrinkage of 10%. For example, at the end of the sintering joining process, the second component may in this case have shrunk by a further 10%, while the first component may have shrunk only by a further 5%. A usual total shrinkage for MIM materials may in this case be in particular 15-18%.

According to a further embodiment of the present disclosure, a contact pressure between the first component and second component while the sintering joining process is being carried out may be settable by way of a suitable dimensioning, choice and/or setting of the opening or of the slot.

The dimension of the gap may take account of the different shrinkage on account of the possibly differently configured degrees of compaction of the first component and second component, such that, during the shrinking operation, the surfaces of the first component and second component move together and ultimately come into contact. If for example one component is now intended to shrink even further, a force action on the other component can be applied via this further shrinkage. Given suitable dimensioning, it is thus possible, while the sintering joining process is being carried out, for the surfaces of the first component and second component to come into contact, or to experience a different or additional bearing force or contact pressure.

According to a further embodiment of the present disclosure, a directed force action of the contact pressure between the first component and second component while the sintering joining process is being carried out may be settable by way of a suitable dimensioning, choice and/or setting of the opening or of the slot.

Preferably, the opening is an inherently closed opening, for example a circle, an oval, a slot or rectangle, square or the like. If the second component is now introduced into the first component, it is possible for example for the slot or the opening to be dimensioned in a locally larger manner compared with other slot subregions or portions. As a result, in the scope of shrinkage while the sintering joining process is being carried out, it is possible for example for those surfaces of the first component and second component that are at a smaller distance or have smaller dimensioning of the slot to come into contact with one another first, while other portions, having possibly larger dimensioning of the slot, come into contact with one another or generate a contact pressure only later, if at all. By way of such a directed force action, it is possible for example for the first component and the second component to be oriented with respect to one another while the sintering joining process is being carried out.

According to a further embodiment of the present disclosure, a joining paste may be provided between the first component and the second component.

A joining paste can be composed for example of the same material as or a similar material to the first and/or the second component and can produce a preferred joint between the first component and the second component as part of the joining process. In this context, the joining paste can compensate for example for irregularities in the surface of the first component and of the second component that may arise because of inaccurate machining. Joining pastes can be adapted to the specific application, for example being materially identical to the materials of the components to be joined, or merely being materially similar, for example having a smaller particle size and, as a result, being quicker to melt, for example. Formation of the joining paste from a different type of material is likewise conceivable, it being possible, by way of example, for the joining paste to comprise materials with a higher activation energy.

According to a further embodiment of the present disclosure, the first component and the second component may have a shape such that, after the sintering joining process has been carried out, a form-fitting joint is producible.

For example, as a result of an undercut configuration of the first component and of the second component in the overlap region, i.e. in the region of the opening, it is possible for not just a force-fitting sintered joint to be produced. For example, suitable grooves, beads and complementary elevations and depressions can be provided on mutually oriented surfaces of the first component and second component, in particular in the region of the opening, these engaging with one another while the sintering joining process is being carried out and providing a form-fitting joint in addition to the force-fitting joint.

According to a further embodiment of the present disclosure, the first component and/or the second component may be formed from a material from the group consisting of a ceramic material, a metal material, a material containing nickel, a material containing cobalt, IN713LC alloy, IN718 alloy, CM247 alloy, Haynes25 alloy and Hastelloy X alloy.

In this case, a nickel-based alloy, or CM247LC alloy, may be composed in particular as follows, based on a mass percentage: Ni: balance; Co: 9.25%; Cr: 8.2%; W: 9.52%; Al: 5.5%; Ta: 3.16%; Hf: 1.34%; Ti: 0.8%; Mo: 0.53%; B: 0.013%; C: 0.06%; Si: <0.01%; S: 0.0017%, Zr: 0.015%.

In this case, a cobalt-based alloy, or Hayne25 alloy, may be composed in particular as follows, based on a mass percentage: Co: balance; C: 0.05-0.15%; Ni: 9.0-11.0%; Fe: <=3.0%; Si: <=1.0%; Mn: 1.0-2.0%; Cr: 19.0-21.0%; W: 14.0-16.0%; P: <=0.03%; S: <=0.03%.

In this case, a nickel-chromium-molybdenum-tungsten alloy, or Hastelloy X alloy, may be composed in particular as follows, based on a mass percentage: Ni: balance; C: <=0.01%; Si: <=0.08%; Mn: <=1.0%; P: <=0.025%; S: <=0.01%; Co: <=2.5%; Cr: 14.5-16.5%; Fe: 4.0-7.0%; Mo: 15.0-17.0%; V: <=0.35%; W: 3.0-4.5%.

According to a further embodiment of the present disclosure, the first component and the second component may have a combination of sintered states from the group consisting of brown part and brown part, brown part and pre-sintered component, pre-sintered component and pre-sintered component, pre-sintered component and fully sintered component, and fully sintered component and fully sintered component.

In particular with identical or similar sintered states, for example brown part and brown part, or pre-sintered and pre-sintered, different shrinkage may be realized on account of different materials or on account of a different binder content in the feedstock (powder/binder mixture).

According to a further embodiment of the present disclosure, the part may be selected from the group consisting of blade airfoil, blade airfoil with tip shroud and a pair of blade airfoils.

Such blade airfoils are used in particular for compressor applications or for turbine applications. A configuration of a part as a part for the nozzle guide vane or as a liner for the combustion chamber of an engine is also conceivable. Such fields of application of the parts may demand a particularly complex geometric structure of a part, which are not producible by a conventional production method or by a sintering joining method in one step, i.e. the production of a part as an integral part from an integral green compact or brown compact, or is only producible thereby with increased effort (for example by means of complex supporting structures and complicated finishing work).

Exemplary embodiments of the present disclosure are described in the following text with reference to the figures.

In the figures:

FIG. 1 shows a sectional side view of a gas turbine engine according to the present disclosure;

FIGS. 2A to D show a first example of an arrangement of components to be joined, according to the present disclosure;

FIGS. 3A and B show examples of configurations of parts produced according to the method of the present disclosure;

FIG. 4 shows a further configuration of a part produced according to the present disclosure;

FIGS. 5A, B and C show examples of configurations of the first component and second component according to the present disclosure; and

FIG. 6 shows a method for producing a part for a turbomachine according to the present disclosure.

FIG. 1 illustrates a gas turbine engine 10 having a main axis of rotation 9. The engine 10 comprises an air intake 12 and a fan 23 that generates two air flows: a core air flow A and a bypass air flow B. The gas turbine engine 10 comprises a core 11 that receives the core air flow A. When viewed in the order corresponding to the axial direction of flow, the core engine 11 comprises a low-pressure compressor 14, a high-pressure compressor 15, a combustion device 16, a high-pressure turbine 17, a low-pressure turbine 19, and a core thrust nozzle 20. An engine nacelle 21 surrounds the gas turbine engine 10 and defines a bypass duct 22 and a bypass thrust nozzle 18. The bypass air flow B flows through the bypass duct 22. The fan 23 is mounted on the low-pressure turbine 19 by means of a shaft 26 and is driven by said turbine.

During operation, the core air flow A is accelerated and compressed by the low-pressure compressor 14 and directed into the high-pressure compressor 15, where further compression takes place. The compressed air exhausted from the high-pressure compressor 15 is directed into the combustion device 16, where it is mixed with fuel and the mixture is combusted. The resultant hot combustion products then expand through the high-pressure and low-pressure turbines 17, 19 and as a result drive the latter, before being exhausted through the nozzle 20 to provide some propulsive thrust. The high-pressure compressor 15 is driven by the high-pressure turbine 17 via a connecting shaft. In general, the fan 23 provides the majority of the propulsive thrust.

It should be noted that the expressions “low-pressure turbine” and “low-pressure compressor”, as used herein, can be taken to mean the lowest-pressure turbine stage and lowest-pressure compressor stage (i.e. not including the fan 23), respectively, and/or the turbine and compressor stages that are connected together by the connecting shaft 26 with the lowest rotational speed in the engine (i.e. not including the gearbox output shaft that drives the fan 23). In some documents, the “low-pressure turbine” and the “low-pressure compressor” referred to herein may alternatively be known as the “intermediate-pressure turbine” and “intermediate-pressure compressor”. Where such alternative nomenclature is used, the fan 23 can be referred to as a first, or lowest-pressure, compression stage.

Other gas turbine engines to which the present disclosure can be applied can have alternative configurations. For example, engines of this type can have an alternative number of compressors and/or turbines and/or an alternative number of connecting shafts. By way of further example, the gas turbine engine shown in FIG. 1 has a split flow nozzle 20, 22, meaning that the flow through the bypass duct 22 has its own nozzle that is separate to and radially outside the core engine nozzle 20. However, this is not limiting, and any aspect of the present disclosure can also apply to engines in which the flow through the bypass duct 22 and the flow through the core 11 are mixed or combined before (or upstream of) a single nozzle, which can be referred to as a mixed flow nozzle. One or both nozzles (whether mixed or split flow) can have a fixed or variable area. Although FIG. 1 relates to a turbofan engine, the disclosure can apply, for example, to any type of gas turbine engine, for example an open rotor engine (in which the fan stage is not surrounded by an engine nacelle) or a turboprop engine.

The geometry of the gas turbine engine 10 and components thereof is/are defined by a conventional axis system, comprising an axial direction (which is aligned with the axis of rotation 9), a radial direction (in the bottom-to-top direction in FIG. 1), and a circumferential direction (perpendicular to the view in FIG. 1). The axial (X direction), the radial (Y direction) and the circumferential direction (Z direction) extend perpendicular to one another.

Referring now to FIGS. 2A to D, a first example of an arrangement of components to be joined, according to the present disclosure, is provided.

FIGS. 2A and 2B illustrate the state before the sintering joining process is carried out, while FIGS. 2C and D depict the state after the sintering joining process has been carried out.

FIG. 2A illustrates a side view and FIG. 2B a view from above of a first component 32 a and of a second component 32 b. The two components 32 a, b are provided in order to produce a part 30. The components 32 a, b are illustrated as geometrically simple shapes, in order to clarify the principle of the present disclosure without distracting from the technical teaching. For a specific application, the individual geometric structures of the components 32 a, b may of course be configured in a more complex manner.

The second component 32 b has an opening 34 a, into which the first component 32 a is introduced. By way of example, in FIGS. 2A and B, the opening 34 a is illustrated as a rectangular opening (cf. FIG. 2B), into which the first component 32 a may be introduced. The opening 34 a is dimensioned such that, after the first component 32 a has been introduced into the opening 34 a in the second component 32 b, a slot 36 a, b, c, d remains between the first component 32 a and the second component 32 b. As is apparent from FIG. 2B, a slot 36 a, 36 b, 36 c, 36 b is arranged on each side of the exemplary rectangle of the opening 34 a. The dimensions of the slots 36 a to 36 d are by way of qualitative example and not quantitatively definitive. Ultimately, the opening 34 a is intended to be configured to allow the first component 32 a to be introduced into the opening 34 a in the second component 32 b, such that it is accommodated and at most has a small amount of play. The first component 32 a has a higher degree of compaction than the second component 32 b. This means that, in a sintering joining process, the dimensions of the first component 32 a do not change to the same degree as the dimensions of the second component 32 b. In other words, the first component 32 a exhibits less shrinkage than the second component 32 b. This has the result, as illustrated in FIG. 2C and in particular FIG. 2D, that the opening 34 a and thus the slots 36 a, b, c, d close up substantially completely after the sintering joining process has been carried out, and form a sintered joint 38. The sides of the opening 34 a thus shrink more than the dimensions of the first component 32 a introduced into the opening 34 a. As can be seen in FIG. 2C, the opening 34 b is smaller, in terms of its dimensions, than the opening 34 a in FIGS. 2A and 2B. In particular, FIGS. 2C and D do not have slots 36 a, b, c, d between the first component 32 a and the second component 32 b; rather, a sintered joint 38 is formed.

Four contact pressures Fa1 , Fa2, Fa3, Fa4 are illustrated in FIG. 2D. As a result of shrinkage of the second component 32 b onto the first component 32 a, the sides of the opening 34 a (as opening 34 b) come into contact with the sides of the first component 32 a at a particular time during the sintering joining process. If the sintering joining process is now continued, and thus the shrinkage, or the different shrinkage of the first component 32 a and second component 32 b, continues, a contact pressure Fa1, Fa2, Fa3, Fa4 of the second component 32 b on the first component 32 a results. This contact pressure may form a preferred sintered joint 38. Depending on the design, all the contact pressures may not always take effect. For example, only Fa1 and Fa3 or Fa2 and Fa4 may act, depending on the setting of the gap dimensions and the degrees of shrinkage.

Referring now to FIGS. 3A and B, examples of configurations of parts produced according to the method of the present disclosure are shown.

FIGS. 3A and 3B show different embodiments of a blade airfoil, as provided for example for turbine applications in the aviation sector. The parts 30 in FIGS. 3A and B are, nevertheless, first of all illustrated schematically in a qualitative manner.

FIGS. 3A and B show a further development of the production method 50 of the present disclosure, wherein a part 30 is produced from two components 32 a, b (with the parts 32 a, c being assumed to be configured as an integral part 32 a) or from three components 32 a, b, c in a common sintering joining process or in two successive sintering joining processes. In this case, the first, second and third components 32 a, b, c can have identical or similar, or different sintered states. Thus, it is possible, for example, for the two components first of all to be moved together in an unsintered state and to be pre-sintered or fully sintered. Subsequently, a further component may be added and joined in a continued sintering joining process or a second sintering joining process. As a result of the subdivision into two sintering joining processes or the successive adding of the third component, only the first component and the second component have a state with a higher degree of compaction and thus reduced shrinkage.

Illustrated in FIGS. 3A and B is a part 30 consisting of a first component 32 a, for example a blade airfoil, that is intended to be joined to a second component 32 b, for example a tip shroud, and a component 32 c, for example a root element. It is also conceivable for two components 32 a, 32 b or 32 a, 32 c to be configured in one piece or integrally and then to be joined to the respectively other component 32 c, 32 b.

In the event that all three components 32 a, 32 b, 32 c are intended to be joined separately, it is possible for the two components 32 b and 32 c each to have an opening 34, into which the component 32 a can be introduced successively or simultaneously. After the sintering joining process has been carried out, the openings 34 are closed, as described in FIGS. 2A to 2D.

Thus, after a sintering joining process has been carried out, a complex part 30 results, that would have been only very difficult to produce integrally, that is to say in one processing step, if a single sintering joining process had been used.

Referring now to FIG. 4, a further configuration of a part according to the present disclosure is shown.

In contrast to FIGS. 2A and B, in FIG. 4, in addition to the components 32 a, 32 b, a joining paste 40 is introduced into the opening 34 a. For example, in FIG. 4, the introduced joining paste 38 closes the opening 34 a substantially completely, wherein configurations are also conceivable in which, in spite of the introduction of joining paste 40, a residual slot 36 a, b, c, d of the opening 34 a remains.

A joining paste 40 consists here of comparable or similar materials to the first component 32 a and the second component 32 b. The joining paste 40 is preferably used to assist the production of joints 38 between the first component 32 a and the second component 32 b in that the joining paste 40 can compensate for surface irregularities in the first and the second component 32 a, b. In FIG. 4, joining paste 40 is illustrated in a purely qualitative manner and is not true to scale.

Referring now to FIGS. 5A, B and C, different configurations of the opening 34 a and of the transition between the first component 32 a and second component 32 b according to the present disclosure are shown.

FIGS. 5A to C illustrate a substantially fully sintered state, and thus a state with a formed opening 34 b.

FIG. 5A shows an opening 34 b that has been formed only partially in the second component 32 b. In other words, the first component 32 a is received in the second component 32 but cannot pass all the way through the latter. Rather, the first component 32 a butts, inside the second component 32 b, against material of the second component 32 b. As a result, preferred positioning for carrying out the sintering joining process can be achieved. Particularly preferably, the upper side, illustrated in FIG. 5A, of the component 32 a may be formed not in a rectilinear manner, but rather for example in a manner tapering to a point or wedge, wherein the rear side of the opening 34 b may have a complementary shape. As a result, easy positioning, before and during the sintering joining process, of the first component 32 a and second component 32 b with respect to one another can be achieved.

In FIG. 5B, the flanks of the second component 32 b are provided with an overhang 44 in the transition region from the first component 32 a to the second component 32 b. As a result a preferred joint 38 can be produced, since the transition from the first component to the second component 32 a, b is formed substantially as a gradual geometric material transition after the sintering joining process has been carried out. A part 30 produced in this way may be more resilient than for example a part according to FIG. 5A. In addition, such a design allows an increase in the joining area, and this may prove advantageous with regard to possible force transmission.

To a certain extent, FIG. 5C provides a combination of FIGS. 5A and 5B. In this case, the circular or arcuate transition 44 from the first component 32 a to the second component 32 b, or the gradual transition 44 from the first component 32 a to the second component 32 b, is formed on the first component 32 a. Thus, the first component 32 a can be introduced into the opening 34 a in the second component 32 b, but then butts against the second component 32 b with the overhang 44 and cannot pass further into the opening 34 a in the second component 32 b. In this way, too, as part of the preparatory actions for a sintering joining process, easy positioning of the first component 32 a and the second component 32 b with respect to one another and an increase in the joining area can be realized.

Referring now to FIG. 6, a method for producing a part for a turbomachine according to the present disclosure is provided.

The method 50 for producing a part 30 for a turbomachine, in particular for an aircraft engine, has the steps of providing 52 a first component 32 a that has a first sintered state with a first degree of compaction; providing 54 at least one second component 32 b that has a second sintered state with a second degree of compaction; wherein the second degree of compaction is lower than the first degree of compaction; and wherein the at least one second component 32 b has an opening 34, into which a portion of the first component 32 a is introducible; and wherein the opening 34 is dimensioned in such a way as to close substantially completely during a sintering joining process, in order to form a force-fitting sintered joint 38 with the first component 32 a; introducing 56 the first component 32 a into the opening 34; and carrying out the sintering joining process.

It goes without saying that the invention is not limited to the embodiments described above and that various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features can be employed separately or in combination with any other features, and the disclosure extends to and includes all combinations and sub-combinations of one or more features that are described herein.

Finally, it should be noted that terms such as “having” or “comprising” do not exclude other elements or steps and that “a” or “an” does not exclude a plural. Elements that are described in connection with different embodiments can be combined. Reference signs in the claims should not be interpreted as limiting.

LIST OF REFERENCE SIGNS

-   9 Main axis of rotation -   10 Engine -   11 Core -   12 Air intake -   14 Low-pressure compressor -   15 High-pressure compressor -   16 Combustion device -   17 High-pressure turbine -   18 Bypass thrust nozzle -   19 Low-pressure turbine -   20 Core thrust nozzle -   21 Engine nacelle -   22 Bypass duct -   23 Fan -   A Core air flow -   B Bypass air flow -   26 Connecting shaft -   30 Part -   32 a,b,c First, second, third component -   34 a,b Opening -   36 a,b,c,d Slot -   38 Sintered joint -   Fa1,Fa2,Fa3,Fa4 Contact pressure -   40 Joining paste -   42 Form-fitting joint -   44 Overhang -   50 Method for producing a part -   52 Providing the first component -   54 Providing the second component -   56 Introducing the first and second component -   58 Carrying out the sintering joining process 

1. A method for producing a part for a turbomachine, in particular for an aircraft engine, having the steps of: providing a first component that has a first sintered state with a first degree of compaction; providing at least one second component that has a second sintered state with a second degree of compaction; wherein the second degree of compaction is lower than the first degree of compaction; and wherein the at least one second component has an opening, into which a portion of the first component is introducible; and wherein the opening is dimensioned in such a way as to close substantially completely during a sintering joining process, in order to form a force-fitting sintered joint with the first component; introducing the first component into the opening; and carrying out the sintering joining process.
 2. The method according to claim 1, wherein, before the sintering joining process is carried out, a slot is provided, in particular in the region of the opening, between the first component and second component, and wherein the slot is closed substantially completely after the sintering joining process has been carried out.
 3. The method according to claim 1, wherein the second component shrinks more than the first component while the sintering joining process is being carried out, with the result that the opening or the slot closes substantially completely.
 4. The method according to claim 1, wherein a contact pressure between the first component and second component while the sintering joining process is being carried out is settable by way of a suitable dimensioning, choice and/or setting of the opening or of the slot.
 5. The method according to claim 1, wherein a directed force action of the contact pressure is settable by way of a suitable dimensioning, choice and/or setting of the opening or of the slot.
 6. The method according to claim 1, wherein a joining paste is provided between the first component and the second component.
 7. The method according to claim 1, wherein the first component and the second component have a shape such that, after the sintering joining process has been carried out, a form-fitting joint is producible.
 8. The method according to claim 1, wherein the first component and the second component are formed from a material from the group consisting of a ceramic material, a metal material, a material containing nickel, a material containing cobalt, IN713LC alloy, IN718 alloy, CM247 alloy, Haynes25 alloy and Hastelloy X alloy.
 9. The method according to claim 1, wherein the first component and the second component have a combination of sintered states from the group consisting of brown part and brown part, brown part and pre-sintered component, pre-sintered component and pre-sintered component, pre-sintered component and fully sintered component, and fully sintered component and fully sintered component.
 10. The method according to claim 1, wherein the part is selected from the group consisting of blade airfoil, blade airfoil with tip shroud, a pair of blade airfoils, part for the nozzle guide vane and liner for the combustion chamber.
 11. A part for a turbomachine, in particular for a gas turbine engine for an aircraft, and more particularly an aircraft engine, produced by the method according to claim
 1. 12. Gas turbine engine for an aircraft, having at least one part according to claim
 11. 